The C++ c_str(), length(), data() and strlen() member function program example
Compiler: Visual C++ Express Edition 2005
Compiled on Platform: Windows XP Pro SP2
Header file: Standard
Additional library: none/default
Additional project setting: Set project to be compiled as C++
Project -> your_project_name Properties -> Configuration Properties -> C/C++ -> Advanced -> Compiled As: Compiled as C++ Code (/TP)
Other info: none
To do: Using the C++ basic_string member functions: c_str() to convert the contents of a string as a C-style, null-terminated, string, length() to return the current number of elements in a string, data() to convert the contents of a string into an array of characters and strlen() to return the C-style string length.
To show: How to use the C++ basic_string c_str(), length(), data() and strlen() member functions in C++ programming
// the C++ c_str(), length(), data() and strlen() program example
#include <string>
#include <iostream>
using namespace std;
int main(void)
{
string str1("Testing the c_str");
cout<<"The original string object str1 is: "<<str1<<endl;
cout<<"Operation: str1.length()"<<endl;
cout<<"The length of the string object str1 = "<<str1.length()<<endl<<endl;
// a string to an array of characters conversion
const char *ptr1 = 0;
ptr1= str1.data();
cout<<"Operation: ptr1= str1.data()"<<endl;
cout<<"The string object pointed by ptr1 is: "<<ptr1<<endl;
cout<<"\nOperation: strlen(ptr1)"<<endl;
cout<<"The length of character array str1 = "<<strlen(ptr1)<<endl<<endl;
// a string to a C-style string conversion
const char *cstr1 = str1.c_str();
cout<<"Operation: *cstr1 = str1.c_str()"<<endl;
cout<<"The C-style string c_str1 is: "<<cstr1<<endl;
cout<<"\nOperation: strlen(cstr1)"<<endl;
cout<<"The length of C-style string str1 = "<<strlen(cstr1)<<endl;
return 0;
}
Output example:
The original string object str1 is: Testing the c_str
Operation: str1.length()
The length of the string object str1 = 17
Operation: ptr1= str1.data()
The string object pointed by ptr1 is: Testing the c_str
Operation: strlen(ptr1)
The length of character array str1 = 17
Operation: *cstr1 = str1.c_str()
The C-style string c_str1 is: Testing the c_str
Operation: strlen(cstr1)
The length of C-style string str1 = 17
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